The present invention relates to a sealing system for shutoff units which is of the type comprising two substantially ring-shaped sealing units, one of which is sealingly or tightly connected with the housing or the blocking element of the shutoff unit and the other of which is either sealingly connected with the blocking element or the housing, respectively, or is formed thereat itself, and the sealing elements for accomplishing the shutoff action can be pressed against one another by a closing movement of the blocking element. The one sealing element is constructed as a thin-wall body of substantially undulated or wave-shaped cross-section which is elastically deformable under the action of the closing force, this thin-wall body extending over the ring width of the corresponding sealing element and in the closed position, while deforming its wall, bearing by means of the wave peaks protruding from one side of the thin-wall body at the other sealing element at least at two ring regions with line contact. The blocking element or housing which is operatively associated with the thin-wall body has, beneath these ring regions, free deformation spaces for its wall and adjacent such spaces a respective support extending parallel to the ring regions for each wave peak protruding from the other side of the thin-wall body.
Such type sealing systems combine the advantages of so-called "soft" seats with those having metallic seats because, on the one hand, they are also suitable for use at considerably greater operating temperatures than such would be possible in the case of "soft" organic sealing material, and, on the other hand, do not possess any rigid, rather a flexible elastic seat.